Mechanism for supporting grindstones



April 3, 1934.

D. F. THERIAULT MECHANISM FOR SUPPORTING GRINDSTONES Filed Nov. 9, 1932 INVENTOR i ATTORNEY.

Patented Apr. 3, 1934 UNITED STATES PATENT OFFICE MECHANISM FOR SUPPORTING GRINDSTONES Application November 9, 1932, Serial No. 641,854

2 Claims.

This invention relates to the mounting of grindstones and is more especially concerned with means for operatively supporting the large stones used in pulp grinding machines.

5 The common arrangement employed for this purpose comprises a shaft mounted in suitable bearings and provided with right and left-hand screw threaded portions. Two collars having right and left internally threaded hubs are mounted, respectively, on the threaded portions of the shaft and they grip the grindstone between them and thus support it for rotation. During the pulp grinding operation the stone is revolved in such a direction that it tends to 5 screw the collars toward each other and thus acts to tighten the grip of both collars on the stone. This fact, together with the conditions under which the machine operates, makes it extremely difiicult to back off either collar when it becomes necessary to remove the stone for the purpose of replacing it with a new one. In some instances the collars become screwed up so tightly that it is necessary to break the stone in order to get it off the shaft.

I The present invention deals especially with these conditions, and it aims to devise a thoroughly practical solution for the problem presented by them. Stated more specifically, it is the chief object of the invention to devise a grindstone supporting mechanism in which both the clamping of the stone in its operative position and its release preparatory to removing it can be readily accomplished.

The nature of the invention will be readily understood from the following description when read in connection with the accompanying drawing, and the novel features will be particularly pointed out in the appended claims.

In the drawing,

Figure 1 is an end view of a stone supporting mechanism constructed in accordance with this invention; and

Fig. 2 is a view, partly in side elevation and partly in vertical section, of the construction shown in Fig. 1.

In the drawing the grindstone is indicated at 2 and its supporting shaft is shown at 3. This shaft is provided with the usual right and lefthand threaded portions 4 and 5, respectively.

Considering first the parts at the right-hand end,

Fig. 2, of the stone, it will be observed that a bushing 6 is threaded on the shaft and comprises an internally threaded sleeve or hub portion and a flange portion a extending radially from the 5 outer end of said sleeve or hub portion. Fitting bushing and a finage portion to bear against 603 the stone. Two keys 8-8, Fig. 1, carried by the collar are located in registering keyways formed in the bushing and the collar and secure these two parts together for rotation in unison while permitting the collar to slide axially on the bushing. Preferably the collar 7 is recessed to take the flange (1. Several thrust screws 9 are threaded through this flange and bear at their inner ends against the shoulder 10, Fig. 2, of the collar, thus holding this shoulder spaced by a substantial distance, say one-quarter or three-eighths of an inch fromthe inner face of the flange a. Since these screws are subjected to a compressive strain only, a relatively small 7513 number of them is required.

A similar arrangement is provided at the opposite end of the stone, and corresponding parts are indicated by the same, but primed, numerals.

In using this mechanism each bushing with its respective collar may be used exactly as though it were an integral structure, the stone being mounted in the manner customary heretofore. Consequently, with this arrangement the collars tend to tighten on the stone exactly as in the 35 prior practice. When it becomes necessary or desirable to remove the stone, it is simply necessary to back out the screws 99 a short distance so that the collars 7 and 7' can slide away from each other on their respective bushings 6 90 out of the screws 9 and the sliding movement of the collars on their bushings away from the ends of the stone effectually relieves the pressure which otherwise would bind the bushings securely on the threads. Holes 12 are formed in the collars to receive large spanners, or other suit- T able tools, for revolving the collars and their bushings either in tightening the collars against a stone or backing them off to release the stone.

I prefer to chromium plate the bushings 6 and 6 and also the threaded portions of the shaft 3, 110.

or to treat them in some equivalent manner, to prevent the rusting of the threads.

It is not always necessary that both clamping members be made in the manner shown. In other words, a clamp structure like that shown at the right-hand side of Fig. 2 can be successfully used with a clamping collar of the old form at the opposite end of the stone, the release of pressure of the collars on the stone afforded by the former of these constructions being sufficient to relieve the pressure on the threads of both clamps so that they can readily be backed away from each other to release the stone. Usually, however, it is preferable to make both clamps of the construction provided by this invention.

While I have herein shown and described a preferred embodiment of my invention, it will be understood that the invention may be embodied in other forms without departing from the spirit or scope thereof.

Having thus described my invention, what I desire to claim as new is:

l. The combination with a grindstone and a shaft on which said grindstone is mounted for rotation, said shaft including a screw threaded portion, of a bushing internally screw threaded to fit the threaded portion of said shaft, said bushing including a hub portion and a flange portion, a collar having a hub portion mounted on said bushing and including a part shaped to bear against an end face of said stone, means for holding said collar and bushing together against relative rotative movement while permitting said collar to slide axially on said bushing, thrust screws carried by the flange portion of said bushing and bearing against said collar for holding the collar normally spaced from the flange of said bushing, and additional means for engaging the opposite end of said stone and 00- operating with said collar to clamp the stone on the shaft.

2. The combination with a grindstone and a shaft on which said grindstone is mounted for rotation, said shaft including a screw threaded portion, of a bushing internally screw threaded to fit the threaded portion of said shaft, said bushing including a hub portion and a flange portion, a collar mounted on the hub portion of said bushing and shaped to bear against an end face of said stone, means for holding said collar and bushing against relative rotation but permitting the collar to slide axially on the bushing, said collar having a recess to receive the flange of said bushing, a series of screws threaded through said flange and bearing against said collar for forcing said collar against the end of said stone, and additional means for engaging the opposite end of said stone and cooperating with said collar to clamp the stone on the shaft.

DOLORE FRANK THERIAULT. 

